France's hard line toward Tehran at nuclear negotiations will not hurt its businesses when they return to Iran after sanctions are lifted, Foreign Minister Laurent Fabius said on Tuesday.

Next week Fabius will make the first visit to Iran by a French foreign minister in 12 years, following the deal major powers struck with Iran to curb its nuclear program in return for sanctions relief.

Despite a long history of commercial, political and social links with Iran - Iran's revolutionary leader Ayatollah Ruhollah Khomenei even lived in exile near Paris - France took one of the hardest lines of the six powers negotiating the accord.

"It's true that France was very firm," Fabius told France Inter radio. "Will French firms be penalized? My answer is no because in the past we had an important presence in Iran. Our (expertise) is excellent in a lot of fields and the Iranians are serious. You know in foreign policy, I think you lose nothing in being respected."

Fabius will not take business leaders with him on his trip, unlike Germany's Economy Minister Sigmar Gabriel who brought a big commercial delegation as the first senior Western leader to visit Iran since the deal.

But Paris is preparing for the lifting of sanctions, which could begin in the first quarter of 2016 if Iran meets obligations set under the accord endorsed on Monday by the U.N. Security Council.

About 50 senior executives from some of France's top firms are due to be briefed on the Iran nuclear agreement by diplomats later on Tuesday, a senior French diplomat said. France's main business lobby group, the Medef, is sending a delegation comprising about 80 firms to Tehran at the end of September.

Historically, French firms like automaker Peugeot (PEUP.PA) and oil major Total (TOTF.PA) were major players in the Iranian market, but European Union and U.S. sanctions adopted in 2011 scared them away.

Imports from Iran to France fell to just 62 million euros in 2013 from 1.77 billion in 2011. French exports to Iran fell to 494 million euros in 2013 from 1.66 billion euros in 2011, according to French foreign ministry estimates.

French bank BNP Paribas (BNPP.PA) was fined almost 9 billion dollars in 2014 for transactions violating U.S. embargos.

"It's a real issue to see how French firms, international and Americans banks react to the lifting of sanctions, at what speed and with what inhibitions," said a second French diplomat.

"To invest, company bosses need complete safety. They need financing, but banks will only finance if they are sure they won't be penalized later."

France, Britain and Germany have agreed with the United States that their firms would not be penalized for activities in Iran should sanctions be restored after they are lifted.

By Reuters